(define (A x y)
    (cond ((= y 0) 0)
          ((= x 0) (* 2 y))
          ((= y 1) 2)
          (else (A (- x 1)
                   (A x (- y 1)))
          )
    )
)
(display (A 1 10))
(newline)
(display (A 2 4))
(newline)
(display (A 3 3))
(exit)